With the popularization of photo taking and image pickup technologies, current handheld mobile devices such mobile phones etc. are mostly installed with a camera having a flash light. During a backlight photo taking process, a condition that there are some dark portions and some bright portions often occurs in the same frame image; while the automatic exposure algorithm which is widely used in the current image pickup equipment uses an average brightness value of the entire image as a reference value, which will result in the dark portions not being able to be exposed enough and the overall imaging effect being not good. At the same time, the flash light has the following disadvantages:
Firstly, the flash light is fixed, and is focused on the middle section, and when dark regions occur in the surrounding, the compensation of the flash light is limited. Secondly, for the flash light, the average brightness value of the whole image is used as the reference value, and only when the average brightness value is less than a threshold for turning on the flash light, the flash light will turn on. In this case, the interested regions with local dark portions cannot be considered during a backlight photo taking process, and it is also difficult to improve the quality of the picked-up image in the case of backlight.
Therefore, how to provide a backlight compensation technology in which exposure parameters are controllable is a technical problem to be solved by those skilled in the art.